scholarly journals Phase Formation and High-Temperature Stability of Very Thin Co-Sputtered Ti-Al and Multilayered Ti/Al Films on Thermally Oxidized Si Substrates

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2039
Author(s):  
Marietta Seifert ◽  
Eric Lattner ◽  
Siegfried B. Menzel ◽  
Steffen Oswald ◽  
Thomas Gemming
Keyword(s):  
Phase Formation ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ambient Atmosphere ◽  
High Temperature Stability ◽  
Individual Layer ◽  
Cover Layer ◽  
X Ray ◽  
Si Substrates ◽  
20 Nm

Ti-Al thin films with a thickness of 200 nm were prepared either by co-sputtering from elemental Ti and Al targets or as Ti/Al multilayers with 10 and 20 nm individual layer thickness on thermally oxidized Si substrates. Some of the films were covered with a 20-nm-thick SiO 2 layer, which was used as an oxidation protection against the ambient atmosphere. The films were annealed at up to 800 °C in high vacuum for 10 h, and the phase formation as well as the film architecture was analyzed by X-ray diffraction, cross section, and transmission electron microscopy, as well as Auger electron and X-ray photoelectron spectroscopy. The results reveal that the co-sputtered films remained amorphous after annealing at 600 °C independent on the presence of the SiO 2 cover layer. In contrast to this, the γ -TiAl phase was formed in the multilayer films at this temperature. After annealing at 800 °C, all films were degraded completely despite the presence of the cover layer. In addition, a strong chemical reaction between the Ti and SiO 2 of the cover layer and the substrate took place, resulting in the formation of Ti silicide. In the multilayer samples, this reaction already started at 600 °C.

scholarly journals High Temperature Behavior of RuAl Thin Films on Piezoelectric CTGS and LGS Substrates

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1605 ◽  
Author(s):  
Marietta Seifert
Keyword(s):  
Thin Films ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Cross Sections ◽  
Barrier Layer ◽  
High Vacuum ◽  
Temperature Stability ◽  
High Temperature Stability ◽  
Si Substrates ◽  
20 Nm

This paper reports on a significant further improvement of the high temperature stability of RuAl thin films (110 nm) on the piezoelectric Ca 3 TaGa 3 Si 2 O 14 (CTGS) and La 3 Ga 5 SiO 14 (LGS) substrates. RuAl thin films with AlN or SiO 2 cover layers and barriers to the substrate (each 20 nm), as well as a combination of both were prepared on thermally oxidized Si substrates, which serve as a reference for fundamental studies, and the piezoelectric CTGS, as well as LGS substrates. In some films, additional Al layers were added. To study their high temperature stability, the samples were annealed in air and in high vacuum up to 900 °C, and subsequently their cross-sections, phase formation, film chemistry, and electrical resistivity were analyzed. It was shown that on thermally oxidized Si substrates, all films were stable after annealing in air up to 800 °C and in high vacuum up to 900 °C. The high temperature stability of RuAl thin films on CTGS substrates was improved up to 900 °C in high vacuum by the application of a combined AlN/SiO 2 barrier layer and up to 800 °C in air using a SiO 2 barrier. On LGS, the films were only stable up to 600 °C in air; however, a single SiO 2 barrier layer was sufficient to prevent oxidation during annealing at 900 °C in high vacuum.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

The Growth and Characterization of Germanium-Carbon Alloy Thin Films

1992 ◽  
Vol 270 ◽  
Author(s):  
Haojie Yuan ◽  
R. Stanley Williams
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vacuum Chamber ◽  
Optical Band Gap ◽  
High Vacuum ◽  
Optical Absorption Spectroscopy ◽  
Alloy Thin Film ◽  
New Materials ◽  
X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

Low-temperature route to nanoscale P3N5 hollow spheres

2003 ◽  
Vol 18 (10) ◽  
pp. 2359-2363 ◽  
Author(s):  
Hongzhou Gu ◽  
Yunle Gu ◽  
Zhefeng Li ◽  
Yongcheng Ying ◽  
Yitai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Hollow Spheres ◽  
Molar Ratio ◽  
Visible Absorption ◽  
X Ray ◽  
Transmission Electron ◽  
Influence Of Temperature On ◽  
Wide Gap ◽  
20 Nm ◽  
High Degree

Nanoscale hollow spheres of amorphous phosphorus nitride (P3N5) were synthesized by reacting PCl3 with NaN3 at 150–250 °C. Transmission electron microscope images show that the hollow spheres have a diameter of 150–350 nm, and the thickness of the shell is 20 nm. A very small amount of curly films were also found in the sample prepared at 150 °C. The infrared spectrum indicates a high degree of purity. X-ray photoelectron spectroscopy indicates the presence of P and N, with a molar ratio of 1:1.62 for P:N. Ultraviolet-visible absorption spectroscopy shows an absorption band at 265–315 nm. Under photoluminescent excitation at 230 nm, the P3N5 emits ultraviolet light at 305 nm. With a band gap of 4.28 eV, the products may be a wide gap semiconductor. A possible mechanism and the influence of temperature on the formation of the hollow spheres are also discussed.

Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

1999 ◽  
Vol 567 ◽  
Author(s):  
Masayuki Suzuki ◽  
Yoji Saito
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Silicon Surfaces ◽  
Gaseous Mixtures ◽  
X Ray ◽  
Initial Stage ◽  
Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

Growth of SiOx Nanowires by Simple Vapor Transport Method and their Optical Properties

2013 ◽  
Vol 534 ◽  
pp. 141-145 ◽  
Author(s):  
Yuto Hakamada ◽  
Shunji Ozaki
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Silicon Monoxide ◽  
Vapor Transport ◽  
X Ray ◽  
Si Substrates ◽  
Vls Growth ◽  
Transport Method ◽  
Vapor Transport Method ◽  
Scanning Electron

SiOx nanowires were grown on Si substrates by a simple vapor transport method of heating the mixture of silicon monoxide and carbon powders at 1000 °C in a tube of the furnace. The dependence of the growth velocity on the growth temperature and on the radius of nanowires indicates that the SiOx nanowires grow through the vaporliquidsolid (VLS) growth mechanism. The properties of the nanowires are characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL).

scholarly journals Synthesis and characterization of nanoscale composite particles formed by 2D layers of Cu-Fe sulfide and Mg-based hydroxide

2021 ◽  
Author(s):  
Yuri Mikhlin ◽  
Roman Borisov ◽  
Sergey Vorobyev ◽  
Yevgeny Tomashevich ◽  
Alexander Romanchenko ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Localized Surface Plasmon ◽  
X Ray ◽  
Zeta Potentials ◽  
Dielectric Resonance ◽  
Magnetic Dynamic ◽  
20 Nm ◽  
Electron Energy Loss

Two-dimensional phenomena are attracting enormous interest at present and the search for novel 2D materials is very challenging. We propose here the layered material valleriite composed of altering atomic sheets of Cu-Fe sulfide and Mg-based hydroxide synthesized via a simple hydrothermal pathway as particles of 50-200 nm in the lateral size and 10-20 nm thick. The solid products and aqueous colloids prepared with various precursor ratios were examined using XRD, TEM, EDS, X-ray photoelectron spectroscopy (XPS), reflection electron energy loss spectroscopy (REELS), Raman, Mössbauer, UV-vis-NIR spectroscopies, magnetic, dynamic light scattering, zeta potential measurements. The material properties are largely determined by the narrow-gap (less than 0.5 eV) sulfide layers containing Cu+ and Fe3+ cations, monosulfide and minor polysulfide anions but are strongly affected by the hydroxide counterparts. Particularly, Fe distribution between sulfide (55-90%) and magnesium hydroxide layers is controlled through insertion of Al into the hydroxide part and by Cr and Co dopants entering both layers. Room-temperature Mössbauer signals of paramagnetic Fe3+ transformed to several Zeeman sextets with hyperfine magnetic fields up to 500 kOe in the sulfide layers at 4 K. Paramagnetic or more complicated characters were observed for valleriites with higher and lower Fe concentrations in hydroxide sheets, respectively. Valleriite colloids showed negative zeta potentials, suggesting negative electric charging of the hydroxide sheets, and optical absorption maxima between 500 nm and 700 nm, also depended on the Fe distribution. The last features observed also in the REELS spectra may be due to localized surface plasmon or, more likely, quasi-static dielectric resonance. The tunable composition, electronic, magnetic, optic and surface properties highlight valleriites as a rich platform for novel 2D composites promising for numerous applications.

Growth and Characterizations of Indium-Doped Pentacene Thinfilm Prepared by Thermal Co-Evaporation as a Novel Nanomaterial

2015 ◽  
Vol 1131 ◽  
pp. 35-38
Author(s):  
Navaphun Kayunkid ◽  
Annop Chanhom ◽  
Chaloempol Saributr ◽  
Adirek Rangkasikorn ◽  
Jiti Nukeaw
Keyword(s):  
Thin Films ◽  
Carrier Concentration ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Charge Carrier Mobility ◽  
Electrical Measurements ◽  
X Ray ◽  
Force Microscopy ◽  
Vis Spectroscopy ◽  
Hybrid Thin Films

This research is related to growth and characterizations of indium-doped pentacene thin films as a novel hybrid material. Doped films were prepared by thermal co-evaporation under high vacuum. The doping concentration was varied from 0% to 50% by controlling the different deposition rate between these two materials while the total thickness was fixed at 100 nm. The hybrid thin films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD) and UV-Visible spectroscopy to reveal the physical and optical properties. Moreover, the electrical properties of ITO/indium-doped-pentacene/Al devices i.e. charge mobility and carrier concentration were determined by considering the relationship between current-voltage and capacitance-voltage. AFM results identify that doping of indium into pentacene has an effect on surface properties of doped films i.e. the increase of surface grain size. XRD results indicate that doping of metal into pentacene has an effect on preferential orientation of pentacene’s crystalline domains. UV-Vis spectroscopy results show evolution of absorbance at photon energy higher than 2.7 eV corresponding to absorption from oxide of indium formed in the films. Electrical measurements exhibit higher conductivity in doped films resulting from increment of both charge carrier mobility and carrier concentration. Furthermore, chemical interactions taken place inside the doped films were investigated by x-ray photoelectron spectroscopy (XPS) in order to complete the remaining questions i.e. how do indium atoms interact with the neighbor molecules?, what is the origin of the absorption at E > 2.7 eV? Further results and discussions will be presented in the publication.

scholarly journals The Effects of Annealing Temperature on the Structural Properties of ZrB2 Films Deposited via Pulsed DC Magnetron Sputtering

Coatings ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 253 ◽  
Author(s):  
Wei-Chun Chen ◽  
Chao-Te Lee ◽  
James Su ◽  
Hung-Pin Chen
Keyword(s):  
Electron Microscopy ◽  
Magnetron Sputtering ◽  
Structural Properties ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
High Vacuum ◽  
Film Structure ◽  
Dc Magnetron Sputtering ◽  
Cross Sectional ◽  
X Ray

Zirconium diboride (ZrB2) thin films were deposited on a Si(100) substrate using pulsed direct current (dc) magnetron sputtering and then annealed in high vacuum. In addition, we discussed the effects of the vacuum annealing temperature in the range of 750 to 870 °C with flowing N2 on the physical properties of ZrB2 films. The structural properties of ZrB2 films were investigated with X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The XRD patterns indicated that the ZrB2 films annealed at various temperatures exhibited a highly preferred orientation along the [0001] direction and that the residual stress could be relaxed by increasing the annealing temperature at 870 °C in a vacuum. The surface morphology was smooth, and the surface roughness slightly decreased with increasing annealing temperature. Cross-sectional TEM images of the ZrB2/Si(100) film annealed at 870 °C reveals the films were highly oriented in the direction of the c-axis of the Si substrate and the film structure was nearly stoichiometric in composition. The XPS results show the film surfaces slightly contain oxygen, which corresponds to the binding energy of Zr–O. Therefore, the obtained ZrB2 film seems to be quite suitable as a buffer layer for III-nitride growth.

Facile Synthesis and Characterization of Spinel NiFe2O4 Nanoparticles and Studies of Their Photocatalytic Activity for Oxidation of Alcohols

2020 ◽  
Vol 12 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Xiangrong Ma ◽  
Rui Dang ◽  
Jieying Liu ◽  
Fang Yang ◽  
Huigui Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray ◽  
Bet Analysis ◽  
Oxidation Of Alcohols ◽  
20 Nm ◽  
Adsorption Desorption

In this paper, we report a novel and facile approach for the synthesis of spinel NiFe2O4 nanoparticles and studies of its photocatalytic activity for oxidation of alcohols. The as-synthesized catalyst was thoroughly characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), elemental mapping, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and N2 adsorption–desorption isotherm (BET) analysis. The TEM image reveals cubic shapes with an average particle size of 10–20 nm. The as-synthesized spinel NiFe2O4 has proved to be an excellent photocatalyst for oxidation of alcohol to the aldehyde with a conversion of 80% and selectivity of 99%. The catalyst has also proved to be noteworthy as it does not loss its catalytic activity even after five cycles of reuse.

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